1. Field of the Invention
The present invention relates generally to subsea vertical flowline connector, and more particularly pertains to a remote subsea flowline connector which is suitable for the remote connection of a subsea, generally horizontal flowline to a related subsea facility, such as a second flowline or a subsea atmospheric system or a production well such as a satellite well.
The growing worldwide need for energy has expanded the search for oil and gas on the ocean floor to greater depths. At the present time it is contemplated locating oil and gas wells at ocean depths that only a few years ago were considered to be relatively inaccessible. Accordingly, underwater flowline installations and related equipment have been designed to enable workmen, operating from a floating vessel or the like which is remote from the flowline or wellhead, to simply and easily install and replace production flowlines, hydraulic control lines and the like.
Though various forms of underwater flowline and related connectors have been proposed for offshore and the like well installations, no truly satisfactory way has heretofore been found for remotely installing and replacing the flowlines necessary for production and for other subsea connections and functions. The fact that the flowline may be installed at depths ranging up to many thousands of feet requires that equipment be provided which can be installed and operated without diver assistance. Further, the relatively great depths contemplated for offshore installations, and the unpredictable and often extreme forces which may act on the equipment after installation, requires that all of the components, including those provided for such purposes as connecting flowlines and hydraulic control lines, be assembled and supported in such a manner as to be reliably and safely installed despite the often adverse conditions.
2. Discussion of the Prior Art
Hanes, et al. U.S. Pat. No. 3,710,859 discloses a flowline connector of the type in common usage in the prior art. The connector generally includes a looped flowline which ends with a connector at the end thereof being in a generally horizontal position. The connector is designed to remotely connect a flowline to subsea equipment such as submerged wellheads in deep water. In this arrangement the wellhead equipment is first installed in place, the flowline is next lowered from a floating vessel to a position adjacent the wellhead, and is then oriented to place the terminal portion of the flowline in alignment with the associated wellhead equipment, such as the pipes or loops of a Christmas tree assembly connected to the wellhead. After such alignment is secured, a connector and an actuating mechanism are lowered from the floating vessel to a position between the wellhead and the flowline, and the connector is placed in leakproof relation therebetween, with all operations being controlled from the floating vessel. After the connection is made, the runningin string can be released from the connector and raised to the floating vessel. In this horizontally completed connection, a female active component and a male passive component of the flowline connection generally have an overlap engagement of twelve to thirty inches, depending upon the size of the connector. In order to provide for relative movement between the female and male parts of the flowline connection, flexibility in the piping and/or movement of the flowline is necessary. The forces necessary to cause this relative movement between the female and male parts of the flowline connection are applied by large hydraulic cylinder(s) either mounted on the subsea equipment or in a connection tool deployed from a surface vessel.